Robert Bate's hydrometer Pevensey with people gathered around a

with people gathered around a barred window

Three quarter length studio portrait of Peter William Barlow seated with his right hand resting upon a table

wearing a hat with a bow

The material they got on why the Needle was discovered was put in a 30 minute radio show

The River Lea and Stratford Bridge with a covered cart crossing

Robert Bate's hydrometer Pevensey with people gathered around aA hydrometer with hinged wooden case manufactured by Robert Bate. Hydrometers are used to measure the density of liquids. The weighted end is placed into a liquid and the hydrometer sinks to a certain level. The specific gravity can then be read from the liquid level on the vertical scale. ca. 1836